Abstract
We use time-resolved measurements of the evolution of surface and buried layer temperatures to quantify the contribution of ballistic phonons to heat transport on nanometer length scales. A laser pulse heats a 100 nm thick Al film which cools by conduction into a GaAs substrate. The top 120-250 nm of the GaAs substrate is doped with In to create a buried layer with a distinct lattice constant. The cooling of the Al film is monitored by time-domain thermoreflectance and, in the second set of experiments, the heating and cooling of the GaAs:In buried layer are monitored by time-resolved x-ray diffraction. The combination of these data shows that thermal transport by ballistic phonons accounts for nearly 20% of the heat flow across the buried layer on nanosecond time scales.
Original language | English (US) |
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Article number | 075337 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 76 |
Issue number | 7 |
DOIs | |
State | Published - Aug 22 2007 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics